One company is betting that full marijuana legalization for New York is just around the corner.

TerraTech Corp., which specialized in hydroponic plant cultivation, has established a division to explore marijuana cultivation in the northeast.

The team will be headed by marijuana legalization advocate Evan Nison, who is executive director of NORML New Jersey and co-founder of the New York Cannabis Alliance. It will be part of Terra Tech’s subsidiary, GrowOp Technology, which sells equipment for hydroponic greenhouses. A second Terra Tech subsidiary, Edible Garden, trades in culinary herbs, like the living basil often sold in supermarkets. Last year, Edible Garden built a five-acre hydroponic greenhouse in Belvidere, N.J.

“The plan is that once cannabis is legal, we’ll be able to take advantage of those greenhouses,” said Mr. Nison.

GrowOp is also examining sites around New York City and upstate, said Mr. Nison. He expects medical marijuana to become legal this year or next.

In New York, legal medical marijuana appears closer than ever. The Assembly, which has already passed a medical-marijuana bill, plans to include a version of the measure in its one-house-budget bill next week, State of Politics reported. Four Republican senators have recently expressed support for some form of medical marijuana, and Gov. Andrew Cuomo has stated he would sign a bill if the legislature passed it.

But industry veterans say it could be two years before New York state can support a legal marijuana market.

“A company setting up infrastructure to support this new industry, that’s premature,” said Adam Bierman, president of MedMen, a consultancy to legal cannabis businesses.

East Coast states that have legalized marijuana in some form usually started with very restricted pilot programs, Mr. Bierman said, which means a legal marijuana market would be slow to form.

In New Jersey, only three dispensaries have opened since medical marijuana was legalized in 2010.

“People looking to get into business need to understand that, if the bill passes this year (in New York), it could be two years before we see a market,” said Aaron Smith, executive director of the National Cannabis Industry Association, which lobbies for the cannabis industry nationally.

“Developing regulations can take a year, and the application process can take several months,” Mr. Smith said. Marijuana plants would take another six months to mature before their products can be sold. “This isn’t like the governor signs a bill and the next day everyone’s setting up shop.”